This invention constitutes an improvement over the system disclosed and claimed in U.S. Pat. No. 3,445,153 issued May 20, 1969 and which is incorporated herein by reference.
As disclosed in the above patent, if there is a displacement of the image pairs produced in the eyes proportional to the image velocity on a screen, a 3-dimensional viewing effect is obtained. This displacement can be obtained by using two different filters which respectively induce photopic (cone vision) in one eye and scotopic (rod) vision in the other eye. The filters, known as "P and S" filters, cause a spectral shift between the visual sensitivity curves of scotopic and photopic vision known as the Parkinje shift. However, viewers incorporating this principle have not been practical because the effect obtained has been greatly degraded owing to the fact that unfiltered light from ambient sources often reaches the eyes of the users, thereby stimulating rods where only cone vision is desired and cones where only rod vision is desired.
Accordingly, it is an object of the present invention to provide a 3-dimensional viewer employing photopic and scotopic principles which maximizes the 3-dimensional effect,
Another object of this invention is to provide an inexpensive, improved 3-dimensional viewing frame of optimum design which will keep unfiltered ambient light from reaching the user's eyes and thereby intensify the preceived image.
A further object of the present invention is to restrict the viewing area of the spectacle to improve the observed image.